• Journal of Korean Society for Quality Management
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• v.40 no.3
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• pp.359-371
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• 2012

Purpose: Due to the explosive growth and widespread use of smartphones, new business opportunities are emerging. Despite the importance of creating customer value in using smartphone applications, past studies on have mainly focused on functions or factors and specifications that influence users to use the device. Methods: This study is intended to identify how customer dissatisfaction from the use of smartphone application services affects customer sentiment and behavior. The research model is tested via a survey of 290 smartphone application users. Results: The result of this empirical study indicates that customer dissatisfaction significantly affects the user's disappointment and regret in using a service, which are subordinate values of customer emotion. The user's anger is positively associated with 'Negative word of mouth' and 'Complaint', which are subordinate values of customer behavior, but not with an intention to switch to another service. 'Regret' and 'Disappointment' are positively associated with 'Negative word of mouth' and 'Switching intention', but not with 'Making direct complaints'. Finally, customer's negative sentiments are a significant intermediary in the relationship between customer dissatisfaction and behavioral response. Conclusion: Finally, the study offers a more systematic understanding on the phasal response process of customer dissatisfaction in relation to the provision of smartphone application services.

• Journal of IKEEE
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• v.14 no.1
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• pp.55-64
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• 2010

In this paper, we proposed the novel TIGBT with an additional p-type MOS structure to achieve the improved trade-off between turn-off and on-state voltage drop(Vce(sat)). These low on-resistance and the fast switching characteristics of the proposed TIGBT are caused by an enhanced electron current injection efficiency which is caused by additional p-type MOS structure. In the simulation result, the proposed TIGBT has the lower on state voltage of 1.67V and the shorter turn-off time of 3.1us than those of the conventional TIGBT(2.25V, 3.4us).

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.940-946
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• 2015

In this paper, we study a method that amplifies the output gain of a high voltage pulse using 300 kHz or higher frequency. We conducted a study on a method for amplifying the output gain using the resonance between the capacitance components of the load and the parasitic components of the circuit, instead of the conservative method for amplifying the pulse-amplitude by raising the voltage of the power stage. In particular, the method simplifies the circuit configuration throughout the appliance of flyback-type topology instead of the bridge-type. There are advantages that prevent damage from overload and the heat in the output circuit through the hard switching by amplifying the gain of the output voltage applying to the load as given by the capacitance component of the output electrode to the output pulse waveform. This study proposed a method to enhance the spatial and electrical efficiency of the contact-type heating device through the dielectric heating method applied to the field of medical and industrial heating.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.220-229
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• 2017

In this paper, To take advantage a variety of DC power as the boost DC-DC converter design specifications through the inductor L and capacitor C through PSPICE to calculate the best estimate of the value. Boost DC-DC converter with a switch device using IRF840 and reverse recovery time Schottky diodes with excellent with constant current controller using D10SC6M and resistance can be configured to considering the Power LED Module was driven by the production. Converter's switching frequency is 50 kHz, the first Duty Rate was made to increase gradually depending on the value of the detection were, 10 % in the output voltage. As a result, the simulated Boost Power LED driver characteristics is in comparison with the design specifications, 5% or less as the error was approximated. Finally, when input 15 V were offered, a stable output 24 V were obtained. and Dimming Control through the adjustment of brightness and current consumption were possible.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.247.1-247.1
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• 2014

The capacitive coupled plasma is used widely in the semiconductor industries. Especially, the uniformity of the industrial plasma is heavily related with defect ratio of devices. Therefore, the industries need the capacitive coupled plasma source which can generate the uniform plasma and control the plasma's uniformity. To achieving the uniformity of the large area plasma, we designed multi-powered electrodes. We controlled the uniformity by controlling the power of each electrode. After this work, we started to research another concept of the plasma device. We make the plasma chamber that has multi-ground electrodes imaginary (CST microwave studio) and simulate the electric field. The shape of the multi-ground electrodes is ring type, and it is same as the shape of the multi-power electrodes that we researched before. The diameter of the side electrode's edge is 300mm. We assumed that the plasma uniformity is related with the impedance of ground electrodes. Therefore we simulated the imaginary chamber in three cases. First, we connected L (inductor) and C (capacitor) at the center of multi-ground electrodes. Second, we changed electric conductivity of multi-ground electrode. Third, we changed the insulator's thickness between the center ground electrode and the side ground electrode. The driving frequency is 2, 13.56 and 100 MHz. We switched our multi-powered electrode system to multi-ground electrode system. After switching, we measured the plasma uniformity after installing a variable vacuum capacitor at the ground line. We investigate the effect of ground electrodes' impedance to plasma uniformity.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.420-429
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• 2008

This paper describes design procedure and control strategy of HDC(High side DC/DC Converter) and MCU(Motor Control Unit) for diesel hybrid electric vehicle. In designing HDC and MCU for HEV high power density and reliability is strongly needed to meet the demand of automotive industry. In order to achieve the high performance of a controller, MPC5554 based control board is developed. An optimized film capacitor and inductor are also developed for high efficiency driving. Skim 63 IGBT module of SEMIKRON for automotive is used for power switching device. The most efficient cooling model for optimal size and reliability were verified by simulation. These procedures are verified by bench or driving test and the results are present in this paper.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.33-41
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• 2006

In the modem power distribution systems, there are lots of zero-phase current harmonics in the neutral power line due to much usages of the controlled switching devices, various semiconductor power converting systems, OA(Office Automation) equipments, PC etc. In order to minimize the current harmonics a zero-phase neutral line current eliminating reactor (NHER) is designed and analyzed its performance using the finite element program. For the design of NHER a program is developed using C++ program. To verify the program a case model(380/220[V], 200[A]) is designed and analyzed by the developed program. As the results of the optimal design, the core loss is reduced by 26[%] with eliminating of the current harmonics. Especially the ninth harmonics is much reduced as compared with the others. When the design of NHER is adapted to the load of the power system, the eliminating effect and efficiency of the device will be much better

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.2
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• pp.106-112
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• 2007

This paper proposes a hybrid architecture algorithm for fast computation of DCT and DFT via recursive factorization. Recursive factorization of DCT-II and DFT transform matrix leads to a similar architectural structure so that common architectural base may be used by simply adding a switching device. Linking between two transforms was derived based on matrix recursion formula. Hybrid acrchitectural design for DCT and DFT matrix decomposition were derived using the generation matrix and the trigonometric identities and relations. Data flow diagram for high-speed architecture of Cooley-Tukey type was drawn to accommodate DCT/DFT hybrid architecture. From this data flow diagram computational complexity is comparable to that of the fast DCT algorithms for moderate size of N. Further investigation is needed for multi-mode operation use of FFT architecture in other orthogonal transform computation.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1203-1204
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• 2006

Recently, utility network is getting more and more complicated and huge. In addition to, demands of power conversion devices which have non-linear switching devices are getting more and more increased. Consequently, according to the non-linear power semiconductor devices, current harmonics are unavoidable. Those current harmonics flow back to utility network and become one of the reasons which make the voltage distortion. On the other hands, voltage sag from sudden increasing loads is also one of the terrible problems inside of utility network. In order to compensate the current harmonics and voltage sag problem, AF(Active Filter) systems could be a good solution method and SMES(Superconducting Magnetic Energy Storage) system is a very good promising source due to the high response time of charge and discharge. Therefore, the combined system of AF and SMES is a wonderful device to compensate both harmonics current and voltage sag. However, unfortunately SMES needs a superconducting magnetic coil. Because of the introduction of superconducting magnetic coil, quench problem caused by unexpected reasons is always existed. In case of discharge operation, quench is a significantly harmful factor according as it decreases the energy capacity of SMES. Therefore, this paper presents a decision method of the specification of the AF-SMES system considering internal fault condition. Especially, authors analyzed the change of the original energy capacity of SMES regarding to the size of resistance caused by quench of superconducting magnetic coil. Finally, based on this simulation, authors manufactured actual Active Filter System using DSP.

• Macromolecular Research
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• v.17 no.7
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• pp.491-498
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• 2009

New $\pi$-conjugated multi-branched molecules were synthesized through the Homer-Emmons reaction using alkyl-substituted, 3,4-ethylenedioxythiophene-based, thiophenyl aldehydes and octaethyl benzene-l,2,4,5-tetrayltetrakis(methylene) tetraphosphonate as the core unit; these molecules have all been fully characterized. The two multi-branched conjugated molecules exhibited excellent solubility in common organic solvents and good self-film forming properties. The semiconducting properties of these multi-branched molecules were also evaluated in organic field-effect transistors (OFET). With octyltrichlorosilane (OTS) treatment of the surface of the $SiO_2$ gate insulator, two of the crystalline conjugated molecules, 7 and 8, exhibited carrier mobilities as high as $2.4({\pm}0.5){\times}10^{-3}$ and $1.3({\pm}0.5){\times}10^{-3}cm^2V^{-1}s^{-1}$, respectively. The mobility enhancement of OFET by light irradiation ($\lambda$ = 436 nm) supported the promising photo-controlled switching behavior for the drain current of the device.